package com.lxk.common;

import org.commonmark.Extension;
import org.commonmark.ext.gfm.tables.TableBlock;
import org.commonmark.ext.gfm.tables.TablesExtension;
import org.commonmark.ext.heading.anchor.HeadingAnchorExtension;
import org.commonmark.node.Link;
import org.commonmark.node.Node;
import org.commonmark.parser.Parser;
import org.commonmark.renderer.html.AttributeProvider;
import org.commonmark.renderer.html.AttributeProviderContext;
import org.commonmark.renderer.html.AttributeProviderFactory;
import org.commonmark.renderer.html.HtmlRenderer;

import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.Set;
import java.util.List;
/**
 * Created by Lxk on 2020/6/25.
 */
public class Markdown2HtmlUtils {

    /**
     * 增加扩展[标题锚点，表格生成]
     * Markdown转换成HTML
     * @param markdown
     * @return
     */
    public static String markdownToHtml(String markdown) {
        //h标题生成id
        Set<Extension> headingAnchorExtensions = Collections.singleton(HeadingAnchorExtension.create());
        //转换table的HTML
        List<Extension> tableExtension = Arrays.asList(TablesExtension.create());
        Parser parser = Parser.builder()
                              .extensions(tableExtension)
                              .build();
        Node document = parser.parse(markdown);
        HtmlRenderer renderer = HtmlRenderer.builder()
                                            .extensions(headingAnchorExtensions)
                                            .extensions(tableExtension)
                                            .attributeProviderFactory(new AttributeProviderFactory() {
                                                @Override
                                                public AttributeProvider create(AttributeProviderContext context) {
                                                    return new CustomAttributeProvider();
                                                }
                                            })
                                            .build();
        return renderer.render(document);
    }

    /**
     * 处理标签的属性
     */
    static class CustomAttributeProvider implements AttributeProvider {
        @Override
        public void setAttributes(Node node, String tagName, Map<String, String> attributes) {
            //改变a标签的target属性为_blank
            if (node instanceof Link) {
                attributes.put("target", "_blank");
            }
            //给table标签的class属性值为 ui celled table
            if (node instanceof TableBlock) {
                attributes.put("class", "ui celled table");
            }
        }
    }

    /**
     * 测试
     * @param args
     */
    public static void main(String[] args) {
        String table = "| 1 | 2   | 3   |\n" +
                "| ----- | ---- | ----- |\n" +
                "| 22  | 22  | 22    |\n" +
                "| 阿什顿发  | 非固定杆 | 撒阿什顿发 |\n" +
                "\n";
        String a = "[fereli 爱编程](http://www.lirenmi.cn)";
//        System.out.println(markdownToHtmlExtensions(table));
    }

}
